Method for implanting a hip prosthesis and related system

ABSTRACT

A method of implanting a hip joint prosthesis into a patient can include obtaining image data of hip joint anatomy of the patient. Physical activities that the patient desires to participate in subsequent to implanting the hip prosthesis can be determined. A size and an initial placement of the hip joint prosthesis based on the image data can be determined. A desired range of motion of the hip joint prosthesis based on the determined physical activities can be determined. A plan can be created comprising a desired implanted location of the hip joint prosthesis and based on the desired range of motion. The plan can be incorporated onto a guide. The plan can be executed with the guide thereby implanting the hip joint prosthesis into the patient at the desired implanted position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/783,230 filed on Mar. 14, 2013. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to hip arthroplasty and more particularlyrelates to a method for performing hip arthroplasty.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

Prosthetic joints can reduce pain due to arthritis, deterioration,deformation, and the like. Prosthetic hip joints often include a femoralcomponent that is fixed to the patient's femur and an acetabular cupthat is fixed within the patient's pelvis. More specifically, thefemoral component can include a distal stem that extends into thepatient's resected femur and a proximal body having a rounded head thatis received within the acetabular cup. The head can articulate withinthe cup so as to moveably couple the femoral component within theacetabular cup. While traditional hi arthroplasty has achieved relativesuccess in terms of results and patient satisfaction, a need exists toprovide additional refinement of acetabular cup placement and implantorientation to facilitate more active lifestyles.

SUMMARY

A method of implanting a hip joint prosthesis into a patient can includeobtaining image data of hip joint anatomy of the patient. Physicalactivities that the patient desires to participate in subsequent toimplanting the hip prosthesis can be determined. A size and an initialplacement of the hip joint prosthesis based on the image data can bedetermined. A desired range of motion of the hip joint prosthesis basedon the determined physical activities can be determined. A plan can becreated comprising a desired implanted location of the hip jointprosthesis and based on the desired range of motion. The plan can beincorporated onto one of a tool and a guide. The plan can be executedwith the tool or guide thereby implanting the hip joint prosthesis intothe patient at the desired implanted location.

According to additional features, executing the plan with the tool orguide can further comprise providing feedback to a surgeon with the toolor guide. The feedback can be based on an actual position of the hipjoint prosthesis relative to the desired implanted location of the hipjoint prosthesis. A desired orientation of the hip joint prosthesis canbe determined. The desired orientation can include a target inclinationangle and a target anteversion angle. The desired orientation can beincorporated into the plan.

In additional features, the hip joint anatomy of the patient isregistered with the plan. Registering can include performing athree-dimensional scan of the hip joint anatomy. Anatomical surfaces ofthe femur and acetabulum of the hip joint anatomy can be mapped.

The plan can be incorporated onto eyewear worn by a surgeon. The plancan be executed by projecting data related to the plan onto the eyewearworn by the surgeon. In other configurations, the plan can beincorporated onto an electronic display associated with a hip insertioninstrument. The plan can be displayed onto the electronic display. Instill other configurations, the plan can be incorporated onto anacetabular cup insertion instrument.

In some examples, at least one of tactile and audible feedback can beprovided based on an actual position of an acetabular cup of the hipjoint prosthesis relative to the desired implanted location of the hipjoint prosthesis. An impingement and stability analysis can beperformed. The desired implanted position can be modified based ondetecting of at least one of impingement and instability of the hipjoint prosthesis. The plan can be created based on at least one of thehip joint anatomy of the patient and a database of pelves havinganatomical characteristics substantially similar to the patient. In oneexample, obtaining image data can include (i) creating a virtualanatomical three-dimensional model of the patient's hip joint, (ii)obtaining actual partial scan of the patient's hip joint; and (iii)registering the partial scan to the virtual anatomical three-dimensionalmodel.

According to additional examples, a method of implanting a hip jointprosthesis into a patient can include obtaining image data of hipanatomy of the patient. Physical activities that the patient desires toparticipate subsequent to implanting the hip prosthesis can bedetermined. A size and an initial placement of the hip joint prosthesisbased on the image data can be determined. A desired range of motion ofthe hip joint prosthesis based on the determined physical activities canbe determined. A plan can be created comprising a desired implantedlocation of the hip joint prosthesis and based on the desired range ofmotion. The plan can be incorporated onto a visual guide. Animplantation template can be displayed onto the visual guide. Theimplantation template can have information from the plan related to thedesired location and position of the hip joint prosthesis. Theimplantation template can be referenced while implanting the hip jointprosthesis into the patient at the desired implanted position.

Displaying the implantation template can comprise displaying at leastone of a target inclination angle and a target anteversion angle. Anindication of implantation depth of a femoral component and/or anacetabular cup can be displayed. A vector of a femoral componentposition and/or an acetabular cup insertion angle can be displayed.

According to additional examples, a method of implanting a hip jointprosthesis into a patient can include obtaining image data of hip jointanatomy of the patient. Physical activities that the patient desires toparticipate in subsequent implanting the hip prosthesis can bedetermined. A size and an initial placement of the hip joint prosthesisbased on the image data can be determined. A desired range of motion ofthe hip joint prosthesis based on the determined physical activities canbe determined. A plan can be created comprising a desired implantedlocation of the hip joint prosthesis and based on the desired range ofmotion. The plan an be incorporated onto an electrical guide. Thedesired implanted location and position can be provided with theelectrical guide. The electrical guide can be referenced whileimplanting the hip joint prosthesis into the patient at the desiredimplanted position.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples areintended for purposes of illustration only and are not intended to limitthe scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a flowchart of a method of implanting a hp prosthesis into apatient according to one example of the present disclosure;

FIG. 2 is a flowchart of an analysis portion of the method shown in FIG.1;

FIG. 3 is a perspective view of a surgeon performing hip arthroplasty ona patient according to one example of the present disclosure;

FIG. 4 is a perspective view of a view path the surgeon visualizes witha guide loaded with a preoperative plan developed from the method f FIG.1;

FIG. 5 is a first exemplary implantation template created by thepreoperative plan and viewed from a guide according to the presentdisclosure;

FIG. 6 is a perspective view of another guide constructed in accordanceto another example of the present disclosure;

FIGS. 7A-7C are additional exemplary implantation templates created bythe preoperative plan and viewed from a guide according to the presentdisclosure;

FIG. 8 is a perspective view of a three-dimensional scanner used to mapanatomical surfaces of a patient's anatomy; and

FIG. 9 is a flowchart of an optical scanning method according to oneexample of the present disclosure

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

For the purpose of enhancing the understanding of the principles of thepresent disclosure, reference will now be made to the examplesillustrated in the drawings. While specific language will be used todescribe the drawings, no limitation of the scope of the presentdisclosure is intended. The following description will be specificallydirected toward a method of implanting a hip joint prosthesis. It willbe appreciated however, that the present method may be equallyapplicable to methods for implanting other prosthesis including thoseassociated with other joints including, but not limited to, a knee, ashoulder, an elbow and an ankle.

With initial reference to FIG. 1, a method of implanting a hip jointprosthesis into a patient is shown and generally identified at referencenumeral 10. In general, the method 10 illustrates one example of a workflow established between a patient and an orthopedic surgeon to selectan optimal hip joint prosthesis for the particular patient. Moreparticularly, the method 10 allows a surgeon and patient to select areoptimal hip joint prosthesis that will permit the patient to participatein various physical activities identified by the patient. In thisregard, some patients may desire a hip joint prosthesis more suitablefor an active lifestyle while other patients may require a hip jointprosthesis particularly suited for less active lifestyles. As will bediscussed herein, various target implant positions and locations may beparticularly suited for patients wanting to participate in certainphysical activities subsequent to implantation. The method 10 thereforecan provide a custom or patient-specific hip joint prosthesis to thepatient.

At block 12, image data of the hip joint anatomy of the patient isobtained. The image data can be any suitable image data such as, but notlimited to, an X-ray, a CT scan, an MRI, an ultrasound, a fluoroscopicscan or a collection of motion data. It will be appreciated that theimage data may be two-dimensional or three-dimensional. In block 14 thedesired activities of the patient are determined. According to oneexample, the patient can identify physical activities that they desireto participate. Physical activities can include activities of dailyliving. In this regard, some patients may desire a hip joint prosthesisthat can provide the patient with a range of motion suitable forparticipating in such physical activities. It will be appreciated thatthe physical activities can include any physical activity such as, byway of example, yoga, downhill skiing, kick-boxing, rowing, etc.

Once the desired activities of the patient are determined, the methodperforms an analysis generally identified at reference 20 in FIG. 2. Inblock 22 an implant size is determined. In one example, the implant sizecan be determined at least in part by the image data. In general,implant size can comprise a size for all components of the hip jointprosthesis such as a femoral component, an acetabular component, amodular head and a liner. In block 24 an initial implant placement isdetermined. In block 26 a desired range of motion of the jointprosthesis is determined based on the determined physical activities.Those skilled in the art will readily appreciate that certain physicalactivities will require a range of motion that may be different thananother physical activity. In step 30 an impingement and stabilityanalysis is performed. In one example, the impingement and stabilityanalysis can be performed virtually.

In block 32 it is determined whether the p joint prosthesis is stableand impingement free. If the hip joint prosthesis is not stable andimpingement free, the position of the hip joint prosthesis is changed instep 34. If the hip joint prosthesis is stable and impingement free, aplan is created and reviewed with the patient in block 40 (FIG. 1). Asused herein, the term “plan” is used to denote a preoperative planhaving data relating to a target position and orientation of animplanted hip joint prosthesis. As will become appreciated, the plan canbe a data file that can be stored on a physical data storage mediumand/or communicated wirelessly between components in an operating roomincluding, but not limited to, a workstation, a tablet, a mobile phone,a surgical instrument, an implant, a wearable accessory or garment, etc.

The plan can include a desired implanted location of the hip jointprosthesis based on the desired range of motion. The plan canadditionally or alternatively include a desired orientation of the hipjoint prosthesis including a target inclination angle and a targetanteversion angle. The plan may also include an indication of a desiredimplantation depth of components of the hip joint prosthesis includingfemoral component and an acetabular cup. In additional configurations,the plan may also incorporate vector orientations of components of thehip joint prosthesis including the femoral component and the acetabularcup. Furthermore, the plan can be created based on the hip joint anatomyof the patient and/or a database of pelves having anatomicalcharacteristics substantially similar to the patient.

In block 42, the plan is approved by the patient and the doctor. Inblock 44, the plan is generated by way of a mechanical (physical) guideand/or an electrical guide. Various examples of such guides will bedescribed herein. In step 46, the guide is manufactured. In step 48 theguide is delivered to the surgeon. In step 50 the plan is executed usingthe guide. Various examples will be provided herein for executing theplan using the guide.

With reference now to FIG. 3, an exemplary guide 60 according to thepresent disclosure is shown. The guide 60 is in the form of a visualguide and comprises eyewear 62 that may be worn by a surgeon 64. Theguide 60 can include a two or three-dimensional visual image or lightedguidance projected or otherwise viewable with the eyewear 62. The visualimage can include an implantation template (as will be described hereinwith respect to FIGS. 5 and 7A-7C) that includes the desired implantedlocation and orientation of a selected hip joint prosthesis 70.According to one configuration, the plan can be downloadedelectronically onto a memory chip 66 that is incorporated onto the guide60. Those skilled in the art will appreciate that the plan canadditionally or alternatively be communicated to the guide 60wirelessly. In other examples, the plan could reside on a radiofrequency identification (RFID) device that is attached or worn by thepatient.

With reference to FIG. 4, a viewing path 80 provided with the visualguide 60 can further enable the surgeon 64 to view a hologram of a hipjoint 82 including an acetabulum 84 and femur 86 including a femoralhead 88. The hologram may enable the surgeon to view skeletal anatomy ofthe hip joint 82 while the skeletal anatomy is otherwise blocked fromview by soft tissue.

Turning now to FIG. 5, the guide 60 can also be configured to displaylocation information of the hip prosthesis 70 according to the planincluding a first implantation template 90. Briefly, the hip prosthesis70 can generally include an acetabular cup assembly 96 and a femoralcomponent 98. The acetabular cup assembly 96 can have an acetabular cup100 and a liner 102. The femoral component 98 can include a femoral stem110, an adapter 112 and a femoral ball 114. The first implantationtemplate 90 can include a first vector 92 indicative of a desiredposition of the acetabular cup 100 and a second vector 94 indicative ofa desired position of the femoral stem 110.

With reference now to FIG. 6, another exemplary guide 120 according tothe present disclosure is shown. The guide 120 is in the form of avisual guide and comprises an electronic display 122 incorporated onto ahip insertion instrument 124. The guide 120 can provide a visual imageor lighted guidance projected or otherwise viewable on the electronicdisplay 122. The electronic display 122 can display one or moreimplantation templates collectively identified at reference 140 in FIG.6 and individually identified at references 140A (FIG. 7A), 1403 (FIG.7B) and 1400 (FIG. 7C). Additionally or alternatively, the electronicdisplay 122 can display the first plantation template 90 (FIG. 5). Theimplantation templates 140 include the desired implanted location of aselected hip joint prosthesis 70.

According to one configuration, the plan can be downloadedelectronically onto a memory chip 148 that is incorporated onto the hipinsertion instrument 124. Those skilled in the art will appreciate thatthe plan can additionally or alternatively be communicated to the guide120 wirelessly. In other examples, the plan could reside on a radiofrequency identification (RFID) device that is attached or worn by thepatient.

With reference now to FIGS. 7A, 7B and 70, the exemplary implantationtemplates 140A, 140B and 1400 will be described. The implantationtemplate 140A can include graphics corresponding to the targetanteversion angle (ANT), target inclination angle (INC), leg length (LL)and offset (OS) according to the plan. In this regard, a surgeon canview this information intraoperatively such as on the guide 60 (FIG. 3)or the guide 120 (FIG. 6). The implantation template 140B can includevisual indicators such as lights that illuminate as the cup 100 (orother component of the hip prosthesis 70) approaches a correspondingposition of the plan. The implantation template 1400 can display anactual position of the cup 100 and the desired position of the cup 100.In some implementations, some or all of the implantation templates 90,140A, 140B and 1400 can be displayed concurrently or superimposed on theguide 60 or 120. It will be appreciated that any of the implantationtemplates 90 or 140 disclosed herein may additionally or alternativelybe displayed elsewhere, such as on a workstation, a mobile phone, atablet or other device.

Turning now to FIG. 8, a three-dimensional imaging device or scanner 160may be used to map anatomical surfaces of the femur 86 and acetabulum84. According to one example, various points around the acetabulum 84may be touched (such as with a probe) and stored to register the anatomyof the patient to the plan. Other areas of the patient's anatomy, suchas the femur 86 may additionally or alternatively be registered tocorrelate with the plan. With the anatomical surfaces of the femur 86and acetabulum 84 registered, the location of the anatomy is known. Thisinformation can be used with any of the guides disclosed herein. It willbe further appreciated that the guides disclosed herein are not mutuallyexclusive. In this regard, in some examples a surgeon may use multipleguides while implanting the hip joint prosthesis 70.

With reference now to FIG. 9, an optical scanning method or method ofobtaining image data according to one example of the present disclosureis shown and generally identified at reference numeral 210. As usedherein, the term “joint space” used to generally refer to anatomicallandmarks related to a hip including but not limited to a pelvis, anacetabulum, and a femoral head. In one option, a pre-operative orvirtual patient-specific anatomical three-dimensional (3D) model of apatient can be created at block 238. In one example, an x-ray or othertwo-dimensional (2D) images can be obtained at block 220. In block 222,the 2D images obtained at block 220 can be converted to a 3D statisticalshape model. Additionally or alternatively, the 3D statistical shapemodel can be created by referencing data from known anatomical databasesin block 224. For example, the anatomical databases 224 can have datarepresenting joint spaces from many known patients. This data can beused as a reference to merge with the 2D image data of the patientobtained at block 220 to create a complete virtual 3D statistical shapeof the patient's joint space. In one advantage, the cost associated withobtaining actual 3D images of the patient can be mitigated by requiringonly traditional x-ray images and leveraging known data of theanatomical databases to create a 3D model.

In another example, a CT and/or MRI can be obtained in block 230. Fromthe CT and/or MRI data, a 3D reconstruction of the joint space can becreated in block 232. In this regard, the virtual anatomical 3D model ofa complete joint space can be created at block 238 from either usingtraditional 2D x-ray data (block 220), or using CT/MRI data (block 230).

In block 240, an intraoperative 3D scan of a patient's joint space isobtained. In one example, an incision can be made on the patient andimage data can be obtained such as by laser imaging, white lightimaging, blue light imaging, optical imaging and ultrasound imaging. Itwill be appreciated that in some instances, positional information of apatient's entire joint space may be incomplete from block 240. In thisregard, in many instances, the intraoperative 3D scan obtained in block240 may only represent a small (incomplete) window of data of thepatient's joint space. In block 242, a complete 3D model is created bymapping the (incomplete) 3D scan of the patient's actual joint spacetaken at block 240 with the (complete) virtual anatomical 3D modelcreated in block 238. Explained further, the surface data obtained fromintraoperative 3D scan from block 240 can be registered to the virtualanatomical 3D model from block 238.

In one method, the surface data obtained from the intraoperative 3D scancan be superimposed or layered onto the surface data obtained from thevirtual anatomical 3D model and a best fit analysis of the two surfacestogether can be obtained. In this regard, an efficient method ofregistering the small window of a patient's actual anatomy to a virtualanatomical 3D model can be provided. A complete anatomical 3D model canbe created from otherwise incomplete data obtained from anintraoperative 3D scan. Anatomical landmarks and surface features of thepatient's joint space can be registered to a preoperative image allowinga smart instrument, smart implant or computer navigation equipment toidentify a position and orientation of a patient's anatomy without theneed for physical probes, measurements or other manual means ofidentifying points.

In block 244 a surgeon can determine whether the preoperative plan(discussed above) will be followed or if a surgeon prefers to positionimplants based on a personal plan or personal preferences. Explainedfurther, in some examples, a surgeon may decide to follow thepreoperative plan or, alternatively, may decide once the joint space isopened up, to position an implant in another location/orientation basedupon the surgeon's personal real time analysis of the patient's jointspace. If the surgeon decides to follow the preoperative plan, thepreoperative plan for position and orientation of the stem and cup isincorporated in block 250.

Alternatively, if the surgeon determines to follow personal preference,the surgeon can input parameters for position and orientation of thestem and cup in block 260. When using a surgeon's personal analysis, thesurgeon may decide upon a desired position (including inclination andanteversion for example) of an acetabular cup. The surgeon can thenproceed with intraoperative guidance for position and orientation of thestem and cup in block 262.

In block 256 electronic guidance can be provided. The desired position(either from the preoperative plan, or from the surgeon's preference)can be input onto a smart instrument that can convey to the surgeon whenthe desired orientation and position of the acetabular cup and stem hasbeen attained. In one example, an acetabular inserter may have a guidethat can display actual and desired positions of the acetabular cup (seeFIGS. 6-7C above) to further assist the surgeon in locating theacetabular cup at the desired position and orientation. Such an insertercould convey to the surgeon when the desired position and orientation ofthe acetabular cup has been reached. According to another example, amold can be taken of the joint space such as with putty, molding clay orother medium. The mold can then be optically scanned into a 3D image. Alandmark can be optionally placed in the joint space and be molded withthe anatomy. Optical scanners can be used to collect data from the moldand register or relate the data to a pre-operative image using imagerecognition software.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A system for using eyewear to display aspects ofa preoperative plan during a surgical procedure comprising: memory to:store image data of hip joint anatomy of the patient; store a size of ahip joint prosthesis and an initial placement of the hip jointprosthesis generated based on the image data; store a received inputincluding a target postoperative range of motion of the hip joint; andstore a preoperative plan including a modification of the size or theinitial placement of the hip joint prosthesis, the modification creatinga target implanted location or target size of the hip joint prosthesisbased on the target postoperative range of motion; and eyewear includingan electronic display to: present an implantation template using theelectronic display, the implantation template including information fromthe preoperative plan related to the target implanted location and theinitial placement of the hip joint prosthesis.
 2. The system of claim 1,wherein the image data is x-ray age data.
 3. The system of claim 1,wherein the image data includes data from an anatomical database.
 4. Thesystem of claim 1, wherein to present the implantation template usingthe electronic display includes generating a hologram.
 5. The system ofclaim 1, wherein the electronic device is further to display feedbackbased on an actual position of the hip joint prosthesis relative to thetarget implanted location of the hip joint prosthesis, the feedbackincluding a target angle, the target angle including at least one of atarget inclination angle or a target anteversion angle.
 6. The system ofclaim 1, wherein the electronic device is further to display anindication of implantation depth of at least one of a femoral componentor an acetabular cup.
 7. The system of claim 1, wherein the implantationtemplate is presented including a first vector indicative of the desiredimplanted location of an acetabular cup of the hip joint prosthesis, anda second vector indicative of the desired implanted location of afemoral stem of the hip joint prosthesis.
 8. A system for using eyewearto display aspects of a preoperative plan during a surgical procedurecomprising: memory to: store image data of joint anatomy of the patient,store an initial placement of the joint prosthesis generated based onthe image data; store a received input including a target postoperativerange of motion of the joint; and store a preoperative plan including amodification of the initial placement of the joint prosthesis, themodification creating a target implanted location of the jointprosthesis based on the target postoperative range of motion; andeyewear including an electronic display to: present an implantationtemplate using the electronic display, the implantation templateincluding information from the preoperative plan related to the targetimplanted location and the initial placement of the joint prosthesis. 9.The system of claim 8, wherein the image data is x-ray image data. 10.The system of claim 8, wherein the image data includes data from ananatomical database.
 11. The system of claim 8, wherein to present theimplantation template using the electronic display includes generating ahologram.
 12. The system of claim 8, wherein the electronic device ofthe eyewear is further to display feedback based on an actual positionof the joint prosthesis relative to the target implanted location of thejoint prosthesis, the feedback including a target angle.
 13. The systemof claim 8, wherein the electronic device of the eyewear is further todisplay an indication of implantation depth of an implantation componentof the joint prosthesis.
 14. The system of claim 8, wherein theimplantation template is presented including a vector indicative of thedesired implanted location of an implantation component of the jointprosthesis.
 15. A method for outputting aspects of a preoperative planduring a surgical procedure for display on eyewear comprising: storingimage data of joint anatomy of the patient; receiving a size of a jointprosthesis and an initial placement of the joint prosthesis generatedbased on the image data; generating a target postoperative range ofmotion of the joint; generating a preoperative plan including amodification of the size or the initial placement of the jointprosthesis, the modification creating a target implanted location ortarget size of the joint prosthesis based on the target postoperativerange of motion; and displaying an implantation template using anelectronic display of eyewear, the implantation template includinginformation from the preoperative plan related to the target implantedlocation and the initial placement of the joint prosthesis.
 16. Themethod of claim 15, wherein the image data is x-ray image data orwherein the image data includes data from an anatomical database. 17.The method of claim 15, wherein displaying the implantation templateusing the electronic display includes generating a hologram.
 18. Themethod of claim 15, further comprising displaying, on the electronicdisplay, feedback based on an actual position of the hip jointprosthesis relative to the target implanted location of the hip jointprosthesis, the feedback including a target angle, the target angleincluding at least one of a target inclination angle or a targetanteversion angle.
 19. The method of claim 15, further comprisingdisplaying, on the electronic display, an indication of implantationdepth of at least one of a femoral component or an acetabular cup. 20.The method of claim 15, wherein displaying the implantation templateincludes displaying a first vector indicative of the desired implantedlocation of an acetabular cup of the hip joint prosthesis, and a secondvector indicative of the desired implanted location of a femoral stem ofthe hip joint prosthesis.